NNoonn--nnaattiivvee ppllaanntt ssuurrvveeyyss \ aalloonngg tthhee DDeellttaa aanndd GGuullkkaannaa NNaattiioonnaall WWiilldd aanndd SScceenniicc RRiivveerrss Report prepared for: The Bureau of Land Management – Glennallen Field Office Helen Cortés-Burns, Lindsey Flagstad, Matthew Carlson, and Timm Nawrocki The Alaska Natural Heritage Program, University of Alaska Anchorage May 2010 Table of contents Table of contents .............................................................................................................................................................................................. I List of figures ................................................................................................................................................................................................... III List of tables ....................................................................................................................................................................................................... V Abstract ............................................................................................................................................................................................................. VI Acknowledgments ....................................................................................................................................................................................... VII Introduction ....................................................................................................................................................................................................... 1 Methods ............................................................................................................................................................................................................... 2 Non-native species recorded along the Gulkana ............................................................................................................................... 3 Overview ....................................................................................................................................................................................................... 3 Plot data ......................................................................................................................................................................................................... 5 Conclusions and management recommendations .................................................................................................................... 25 Problematic areas and infestations ........................................................................................................................................... 25 High priority sites and infestations ..................................................................................................................................... 26 Lower priority sites and infestations ................................................................................................................................. 26 Lowest priority infestations ................................................................................................................................................... 27 Factors associated with non-native plant invasion along the Gulkana River ......................................................... 31 Weed propagule source areas and routes of introduction ........................................................................................ 31 Site vulnerability .......................................................................................................................................................................... 34 Weed distribution patterns ........................................................................................................................................................... 36 Weed management recommendations .................................................................................................................................... 36 Non-native plants recorded along the Delta ..................................................................................................................................... 38 Overview ..................................................................................................................................................................................................... 38 Non-native plant populations recorded ........................................................................................................................................ 39 Conclusions and recommendations for the Delta NWSR....................................................................................................... 44 Problematic areas and infestations ........................................................................................................................................... 44 Weed management recommendations .................................................................................................................................... 46 Species factsheets.......................................................................................................................................................................................... 47 Species bios and control recommendations ................................................................................................................................ 47 Alopecurus pratensis (meadow foxtail, NR) ........................................................................................................................... 47 Brassica napus (rapeseed mustard or rutabaga, NR) ........................................................................................................ 48 Bromus inermis ssp. inermis (smooth brome, 62) ............................................................................................................... 48 Capsella bursa-pastoris (shepherd’s purse, 40) ................................................................................................................... 49 Cerastium fontanum (mouse-ear chickweed, 36)................................................................................................................ 50 Chenopodium album (lambsquarters, 37) .............................................................................................................................. 51 Crepis tectorum (narrowleaf hawksbeard, 54) ..................................................................................................................... 51 Melilotus alba (white sweetclover, 81) .................................................................................................................................... 53 Stellaria media (common chickweed, 42) .............................................................................................................................. 55 Trifolium hybridum (alsike clover, 57) ..................................................................................................................................... 55 Trifolium repens (white clover, 59) ........................................................................................................................................... 56 Tripleurospermum inodorum (scentless false mayweed, 48) ........................................................................................ 57 Low priority species ............................................................................................................................................................................... 58 Taraxacum officinale ssp. officinale (common dandelion, 58) ...................................................................................... 58 Poa annua (annual bluegrass, 46) .............................................................................................................................................. 58 Poa pratensis spp. pratensis (Kentucky bluegrass, 52) ..................................................................................................... 58 Poa pratensis ssp. irrigata (spreading bluegrass, 52) ....................................................................................................... 58 Species whose non-nativity is questionable: .............................................................................................................................. 59 Erysimum cheiranthoides (wormseed wallflower) ............................................................................................................. 59 Lepidium densiflorum (common pepperweed, 27) ............................................................................................................. 60 Hordeum jubatum (foxtail barley, 63) ...................................................................................................................................... 60 References ........................................................................................................................................................................................................ 62 I Appendix 1. Example field datasheet used for the 2008 Gulkana National Wild and Scenic River non-native plant survey ....................................................................................................................................................................................................